Abstract: Objective To explore the role of Ezrin in neutrophil elastase (NE)-induced mucin (MUC)5AC production in human HBE16 airway epithelial cells．Methods The HBE16 airway epithelial cells were cultured，transfected with pEGFP-N1-Ezrin-T567D and pEGFP-N1-Ezrin-T567A， respectively， then each group was treated with 0.5 μmol/L NE．The levels of MUC5AC protein in culture medium，MUC5AC protein in cytoplasm，MUC5AC mRNA, and Ezrin protein in culture cells were detected with ELISA，real time-PCR，and immunofluorescence, respectively．Results There was an obvious increasing of MUC5AC protein production and mRNA expression in cells exposed to NE，with elevation of Ezrin protein，all had significant differences when compared with normal control group．Cell transfected with pEGFP-N1-Ezrin-T567D increased MUC5AC secretion in culture medium，P<0.01，compared with single NE-stimulated cells． Ezrin protein were increased, and manily concentrated in cytoplasmic membranes，P<0.05，compared with single NE-stimulated cells． pEGFP-N1-Ezrin-T567A restrained Ezrin expression in cells and decreased MUC5AC protein in culture medium．Conclusion Ezrin is involved in NE-mediated MUC5AC protein secretion but not MUC5AC mRAN expression in HBE16 cells. The phosphrylation of Thr567 site in Ezrin may play a critical role．

Key words: Mucins, secretion, Leukocyte elastase, Ezrin